Another Japanese product would be the Rinnai Energysaver. Gas fired, direct vent, bedroom approved, and they are quiet. I'd suggest a model EX-08 or the EX-11.

Kerosene heaters were popular in the US in the early 80s. But I think there are concerns about their safety. Houses are typically much air tighter these days, so it order to operate it safety a nearby window needs to be opened a small amount for ventilation. This is counter productive for most houses.

You could consider an electric space heater. They are very quiet and safe.